Live opposite the exchange yet only get 12Mbps

Since I moved to a flat that's quite literally next to the exchange I figured that I'd get pretty decent ADSL2 speeds, yet the best I seem to be able to achieve is around 12Mbps (BT checker) which according to CS is just fine. Is this right, or has something gotten a bit messed up?

BT results:

Download speed achieved during the test was - 12.74 Mbps
For your connection, the acceptable range of speeds is 4 Mbps-21 Mbps.
IP Profile for your line is - 13.48 Mbps

Upload speed achieved during the test was - 0.69Mbps
Upstream Rate IP profile on your line is - 0.83 Mbps

Re: Live opposite the exchange yet only get 12Mbps

About a week or so, my best guess is that it might have something to do with me having to fight with my modem to get it to work bridged (turns out the trick is to ignore Plusnet's guidance and pick LLC-Based multiplexing) leading to a bunch of disconnections in the first couple of days, but it's been pretty stable since.

Unsure if it's related, but after asking interleaving to be switched off, a Service Notice popped up on my account noting that I'll be moved over to 21CN by midnight tonight, though according to CS it's already happened. Not really sure why it wasn't from the start..

Re: Live opposite the exchange yet only get 12Mbps

a Service Notice popped up on my account noting that I'll be moved over to 21CN by midnight tonight, though according to CS it's already happened.

It has already happened. Otherwise you'd only be getting 8 meg Sync speed.

Your line is good for about the full monty 24 Meg @ 6dB NM. Your current 9dB NM does not account for the 8-9 Meg reduction you are getting, perhaps only 2-3 Meg of it. However wait a days to see if it settles.

Re: Live opposite the exchange yet only get 12Mbps

Are there any working extensions in the flat ? Have you tried plugging into the test socket behind the lower part of the BTmaster socket, in order to eliminate any internal extension wiring and also the faceplate it's self, ? As said give it a day or so , if no improvement then try the above ,
also have you performed a quiet test using a corded phone 17070 option 2, ?
if there are any noises such as crackling or other noises that are odd present there may be a fault with the line itself

As for your speed, that is currently being restricted by the current Bras IP profile which is set by Bt's woeful DLM Your connection has probably been interleaved which won't help with getting max speeds,
Also the Upstream sync appears to be capped, ask your isp to uncap it , you may get a 1mbps usable upstream rate then ,
If the IP profile doesn't increase then i think the ISP can get it reset , or maybe even disable DLM altogether ,

But IMO getting around 13mbps throughput with a sync of around 14.5-15mbps with a short line, and attenuation figures like yours isn't just fine at all, fine for who the isp?

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.